Projet_SETI_RISC-V/neorv32/sw/example/demo_slink/main.c

// #################################################################################################
// # << NEORV32 - SLINK Demo Program >>                                                            #
// # ********************************************************************************************* #
// # BSD 3-Clause License                                                                          #
// #                                                                                               #
// # Copyright (c) 2023, Stephan Nolting. All rights reserved.                                     #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #
// #################################################################################################


/**********************************************************************//**
 * @file demo_slink/main.c
 * @author Stephan Nolting
 * @brief SLINK demo program.
 **************************************************************************/
#include <neorv32.h>
#include <string.h>


/**********************************************************************//**
 * @name User configuration
 **************************************************************************/
/**@{*/
/** UART BAUD rate */
#define BAUD_RATE 19200
/**@}*/

// Prototypes
void slink_rx_firq_handler(void);
void slink_tx_firq_handler(void);
uint32_t xorshift32(void);


/**********************************************************************//**
 * Simple SLINK demo program.
 *
 * @note This program requires the UART0 and the SLINK to be synthesized.
 *
 * @return =! 0 if execution failed.
 **************************************************************************/
int main() {

  int i;
  uint32_t slink_data;
  int slink_status;

  // capture all exceptions and give debug info via UART0
  neorv32_rte_setup();

  // setup UART0 at default baud rate, no parity bits, no HW flow control
  neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);

  // check if UART0 unit is implemented at all
  if (neorv32_uart0_available() == 0) {
    return -1; // abort if not implemented
  }


  // intro
  neorv32_uart0_printf("\n<<< SLINK Demo Program >>>\n\n");

  // check if SLINK is implemented at all
  if (neorv32_slink_available() == 0) {
    neorv32_uart0_printf("ERROR! SLINK module not implemented.");
    return -1;
  }


  // show SLINK hardware configuration
  neorv32_uart0_printf("# SLINK RX channels: %u (%u FIFO entries each)\n"
                       "# SLINK TX channels: %u (%u FIFO entries each)\n",
                       neorv32_slink_get_link_num(0),
                       neorv32_slink_get_fifo_depth(0),
                       neorv32_slink_get_link_num(1),
                       neorv32_slink_get_fifo_depth(1));

  neorv32_uart0_printf("\nNOTE: This demo program uses SLINK RX/TX channels 0 only.\n\n");


  // reset and enable SLINK module
  neorv32_slink_setup((0b10 << (SLINK_IRQ_RX_LSB + 2*0)) | // RX link 0: IRQ if FIFO becomes not empty
                      (0b11 << (SLINK_IRQ_TX_LSB + 2*0))); // TX link 0: IRQ if FIFO becomes less than half full


  // NEORV32 runtime environment: install SLINK FIRQ handlers
  neorv32_rte_handler_install(SLINK_RX_RTE_ID, slink_rx_firq_handler);
  neorv32_rte_handler_install(SLINK_TX_RTE_ID, slink_tx_firq_handler);
  neorv32_cpu_csr_set(CSR_MIE, 1 << SLINK_RX_FIRQ_ENABLE); // enable SLINK RX FIRQ
  neorv32_cpu_csr_set(CSR_MIE, 1 << SLINK_TX_FIRQ_ENABLE); // enable SLINK RX FIRQ
  neorv32_cpu_csr_set(CSR_MSTATUS, 1 << CSR_MSTATUS_MIE); // enable machine-mode interrupts


  // do some demo transmissions
  neorv32_uart0_printf("-------- TX Demo --------\n");

  for (i=0; i<6; i++) { // try to send 6 data words
    slink_data = xorshift32();
    neorv32_uart0_printf("%i: SLINK TX 0x%x via link 0... ", i, slink_data);

    if (i == 3) {
      neorv32_uart0_printf("[set END-OF-PACKET] ");
      slink_status = neorv32_slink_tx(0, slink_data, 1); // do a "end of packet" transmission (set LST high)
    }
    else {
      slink_status = neorv32_slink_tx(0, slink_data, 0); // "normal" transmission
    }

    if (slink_status == 0) { // successful?
      neorv32_uart0_printf("ok\n");
    }
    else {
      neorv32_uart0_printf("fail; FIFO full\n");
    }
  }


  // check the RX link
  neorv32_uart0_printf("\n-------- RX Demo --------\n");

  for (i=0; i<6; i++) { // try to read 6 data words
    slink_data = 0;
    neorv32_uart0_printf("%i: SLINK RX link 0... ", i);

    slink_status = neorv32_slink_rx(0, &slink_data);
    if (slink_status == 0) {
      neorv32_uart0_printf("received 0x%x\n", slink_data);
    }
    else if (slink_status == 1) {
      neorv32_uart0_printf("received 0x%x [END-OF-PACKET]\n", slink_data);
    }
    else { // == -1
      neorv32_uart0_printf("no data available\n");
    }
  }

  neorv32_uart0_printf("\nProgram execution completed.\n");
  return 0;
}


/**********************************************************************//**
 * SLINK RX interrupt handler.
 **************************************************************************/
void slink_rx_firq_handler(void) {

  neorv32_cpu_csr_write(CSR_MIP, ~(1 << SLINK_RX_FIRQ_PENDING)); // ack FIRQ

  neorv32_uart0_printf(" <<SLINK RX IRQ!>> ");
}


/**********************************************************************//**
 * SLINK TX interrupt handler.
 **************************************************************************/
void slink_tx_firq_handler(void) {

  neorv32_cpu_csr_write(CSR_MIP, ~(1 << SLINK_TX_FIRQ_PENDING)); // ack FIRQ

  neorv32_uart0_printf(" <<SLINK TX IRQ!>> ");
}


/**********************************************************************//**
 * Simple pseudo random number generator.
 *
 * @return Random number.
 **************************************************************************/
uint32_t xorshift32(void) {

  static uint32_t x32 = 314159265;

  x32 ^= x32 << 13;
  x32 ^= x32 >> 17;
  x32 ^= x32 << 5;

  return x32;
}